Touch screens are commonly used as input devices for a variety of products. The usage of touch devices of various kinds is growing sharply due to the emergence of new mobile devices such as Personal Digital Assistants (PDA), tablet PCs and flat panel displays (FPD). Some of these devices use the touch screen as an addition to standard input or output devices, while others are not connected at all to standard keyboards, mice or like input devices, which are deemed to limit their mobility. A stylus or a body part such as one or more fingers touching or hovering over a digitizer sensor may be used to enable user interactions with the underlying computing platform.
As the usage of touch screens increases and the sensor technologies advance, so do the relevant applications. While traditional applications, such as e-mail or web browsing can be well operated using a single touch mechanism, more advanced applications, including, for example, graphic applications, may well benefit from receiving and utilizing simultaneous multiple interactions that may be in the form of simultaneous multiple touches.
In many applications, simultaneous touches by multiple fingers or styli can be used for drawing multiple lines, performing gestures which can initiate operations such as file manipulation, graphic operations etc. The exact recognition of how many interactions, e.g., made by fingers or styli touching the screen, and the locations of such interactions may be crucial for correct and efficient usage of an application, as incorrect recognition may be highly frustrating for a user of the application.
As long as the interactions with a touch screen are well spaced apart from each other, such that there are clear non-touched gaps therebetween, all touches can be univocally detected or identified and used by the underlying system or associated application. However, as the distances between the locations or points of interactions are reduced, e.g., when two or more fingers touching the screen are relatively close to each other, touching each other, or even tightly adjacent to each other, differentiating between the interactions, e.g., determining the number of fingers interacting with a touch screen and/or identifying the touch point of each finger gets more complex. Further, a multiplicity of fingers touching each other can be confused with a larger object or body part which is not usually used for a user interaction, such as a palm or an elbow.
There is thus a need in the art for a system and method for accurately detecting and/or identifying interactions with a touch screen.
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